Ch 8 Mastering Biology

Which of these is exhibiting kinetic energy?

A) a space station orbiting Earth
B) a rock on a mountain ledge
C) an archer with a flexed bow
D)a person sitting on a couch while watching TV
E)the high-energy phosphate bonds of a molecule of ATP

A

"Conservation of energy" refers to the fact that _____.

A) if you conserve energy you will not be as tired
B) the net amount of disorder is always increasing C) no chemical reaction is 100 percent efficient
D) energy cannot be created or destroyed but can be converted from one form to another
E) the entropy of the universe is always increasing

D

Chemical energy is a form of _____ energy.

A) motion
B) kinetic
C) potential
D) entropic
E) heat

C

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?

A) redox
B) cellular respiration
C) digestion
D) anabolism
E) potentiation

B

Which of these are by-products of cellular respiration?

A) heat, carbon dioxide, and water
B) ATP, carbon dioxide, and water
C) ATP and carbon dioxide
D) glucose, carbon dioxide, and water
E) carbon dioxide and water

A

Which of the following statements about the combustion of glucose with oxygen to form water and carbon dioxide (C6H12O6 + 6 O2 → 6 CO2 + 6 H2O) is correct?

A) The free energy lost in this combustion is less than the energy that appears as heat.
B) The entropy of the universe decreases as the result of this reaction.
C) The reverse reaction, making glucose from water and carbon dioxide, must be an exergonic reaction.
D) This is the process of cellular respiration, an anabolic pathway that releases free energy.
E) The entropy of the products is greater than the entropy of the reactants.

E

Which of the following statements about equilibrium of chemical reactions is correct?

A) The equilibrium point of a reaction represents the least stable configuration for that reaction.
B) The equilibrium point is where the system has the highest free energy
C) Reactions can only go in the direction toward equilibrium.
D) A reaction that is at equilibrium is not capable of doing any work.
E) Most reactions in a living cell are close to equilibrium.

D

In this reaction ____ (Reactants AB+CD –> AC+BD, exergonic reaction)

A) entropy has decreased
B) AC is a reactant
C) CD is a product
D) the products have less potential energy than the reactants
E) the products have been rearranged to form reactants

D

In this reaction ____ (Reactants AB+CD –> AC+BD, exergonic reaction)

A) the chemical energy of the products is greater than that of the reactants
B) heat has been released to the environment
C) entropy has decreased
D) the kinetic energy of the reactants is less than that of the products
E) disorder has decreased

B

The following reaction
A –> B + C + heat
is a(n) _____ reaction.

A) endergonic
B) exergonic
C) anabolic
D) exchange
E) dehydration synthesis

B

A(n) _____ reaction occurs spontaneously.

A) exergonic
B) kinetic
C) chemical
D) endergonic
E) anabolic

A

Which of these reactions requires a net input of energy from its surroundings?

A) exergonic
B) endergonic
C) ATP –> ADP + P
D) catabolic
E) hydrolysis

B

In cells, what is usually the immediate source of energy for an endergonic reaction?

A) ADP
B) sugar
C) ATP
D) as spontaneous reactions, endergonic reactions do not need an addition of energy
E) glucose

C

The reaction ADP + P –> ATP is a(n) _____ reaction.

A) endergonic
B) spontaneous
C) exergonic
D) hydrolysis
E) chemical

A

The energy for an endergonic reaction comes from a(n) _____ reaction.

A) glucose + glucose –> maltose
B) ADP + P –> ATP
C) anabolic
D) exergonic
E) synthesis

D

What is the fate of the phosphate group that is removed when ATP is converted to ADP?

A) It is used to convert an ATP into an AQP.
B) It is acquired by a reactant in an exergonic reaction.
C) It is acquired by a reactant in a spontaneous reaction.
D) It is acquired by a reactant in an endergonic reaction.
E) It is broken down into one phosphorus and four oxygen atoms.

D

The graph illustrates a(n) _____ reaction (Reactants have less energy than products)

A) spontaneous
B) hydrolysis
C) exergonic
D) endergonic
E) catabolic

D

Select the INCORRECT association.

A) exergonic … spontaneous
B) exergonic … uphill
C) kinetic energy … motion
D) enzyme … protein
E) potential energy … positional energy

B

What is energy coupling?

A) a barrier to the initiation of a reaction
B) the use of energy released from an exergonic reaction to drive an endergonic reaction
C) the hydrolysis of ATP to ADP + P
D) the use of an enzyme to reduce EA
E) a description of the energetic relationship between the reactants and products in an exergonic reaction

B

What makes up an ATP (Adenosine Triphosphate) molecule?

3 phosphate groups, a ribose group (pentagon), and an adenine group (double ring).

What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule?

A) dehydration decomposition
B) dehydration synthesis
C) hydrolysis
D) anabolism
E) entropic

C

Which has a lower reaction rate?

A) reaction catalyzed by an enzyme
B) uncatalyzed reaction

B

An enzyme is ______ when it loses its native conformation and its biological activity.

Denatured

An enzyme is considered a ______ because it speeds up chemical reactions without being used up.

Catalyst

An enzyme is considered _____ because of its ability to recognize the shape of a particular molecule.

Specific

A ______, such as vitamin, binds to an enzyme and plays a role in catalysis.

Cofactor

When properly aligned, the enzyme and substrate form an enzyme-substrate (ES) _____

Complex

A substrate binds to an enzyme at the ________, where the reaction occurs

Active site

In a catalyzed reaction a reactant is often called a _____

Substrate

In which region does the reaction rate remain constant? (Graph: Reaction rate (Y) vs substrate concentration (X), in region A it spikes up, in region B it curves (concave down), in region C it levels out near the maximum activity)

A) region A
B) region B
C) region C

C

In which region is the enzyme saturated with substrate? (Graph: Reaction rate (Y) vs substrate concentration (X), in region A it spikes up, in region B it curves (concave down), in region C it levels out near the maximum activity)

A) region A
B) region B
C) region C

C

Consider a situation in which the enzyme is operating at optimum temperature and pH, and has been saturated with substrate. What is your best option for increasing the rate of the reaction?

A) Increase the pH.
B) Increase the temperature.
C) Increase the enzyme concentration.
D) Increase the substrate concentration.

C

A(n) ________ inhibitor has a structure that is so similar to the substrate that it can bond to the enzyme just like the substrate.

Competitive

A(n) ________ inhibitor binds to a site on the enzyme that is not the active site.

Noncompetitive

Usually, a(n) ________ inhibitor forms a covalent bond with an amino acid side group within the active site, which prevents the substrate from entering the active site or prevents catalytic activity.

Irreversible

The competitive inhibitor competes with the substrate for the _______ on the enzyme

Active site

When the noncompetitive inhibitor is bonded to the enzyme, the shape of the ______ is distorted

Enzyme

Enzyme inhibitors disrupt normal interactions between an enzyme and its _____

Substrate

You have added an irreversible inhibitor to a sample of enzyme and substrate. At this point, the reaction has stopped completely.

What can you do to regain the activity of the enzyme?

A) Removing the irreversible inhibitor should get the reaction working again.
B) The enzyme is inactive at this point. New enzyme must be added to regain enzyme activity.
C) Adding more substrate will increase the rate of reaction.
D) Adding more inhibitor should get the reaction up to speed again.

B

You have an enzymatic reaction proceeding at the optimum pH and optimum temperature. You add a competitive inhibitor to the reaction and notice that the reaction slows down.

What can you do to speed the reaction up again?

A) Add more inhibitor to speed up the reaction.
B) Add more substrate; it will outcompete the inhibitor and increase the reaction rate.
C) Increase the temperature.
D) Increase the pH.

B

Which of the following statements is most likely to be true in the case of the feedback-regulated enzymatic pathway shown? (Listed P0, E1, P1, E2, P2, E3, P3, E4, P4)

A) P0 binds E4 and activates it.
B) P2 binds E2 and activates it.
C) P4 binds E1 and deactivates it.
D) P3 binds E2 and activates it
E) P4 binds E3 and deactivates it.

C

Which of the following statements about feedback regulation of a metabolic pathway is correct?

A) The compound that regulates the pathway acts as a competitive inhibitor or a positive allosteric regulator.
B) The enzyme that is regulated by feedback inhibition is usually the last enzyme in the metabolic pathway.
C) The final product of a metabolic pathway is usually the compound that regulates the pathway.
D) The products of the pathway become the reactants for a different reaction, and thus products are unable to accumulate.
E) Accumulation of the product of the pathway increases further formation of that product.

C